Abstract

OC-2 plays a vital role in tumor growth, metastasis and angiogenesis, but molecular mechanism how OC-2 regulates angiogenic factors is unclear. We found that OC-2 was highly expressed in HepG2, COLO, MCF-7, SKOV3 cells and rectum carcinoma tissues, and angiogenic factors levels were positively related to OC-2. Then OC-2 KD inhibited the tumor growth, metastasis and angiogenesis process in vitro and vivo. ChIP-Seq showed that 228 target genes of OC-2 were identified and they were associated with tumor growth, metastasis, angiogenesis and signal transduction; OC-2 bound to ZKSCAN3 at promoter region. Luciferase assays showed that ZKSCAN3 was identified as target gene of OC-2 and VEGFA was identified as target gene of ZKSCAN3; OC-2 promoted VEGFA expression via activating ZKSCAN3 transcriptional program. Importantly, OC-2 KD down-regulated VEGFA secretion to suppress tumor angiogenesis of HUVECs. Besides VEGFA, OC-2 was positively correlated with other angiogenic factors HIF-1α, FGF2, EGFL6 and HGF. Meanwhile, ERK1/2 and Smad1 signaling pathways might be related to function of OC-2 driving tumor aggressiveness. We revealed that OC-2 might regulate tumor growth, metastasis, angiogenesis via ERK1/2, Smad1 signaling pathways and regulate VEGFA expression for tumor angiogenesis via activating ZKSCAN3 transcriptional program, indicating that OC-2 was a convincing target to develop novel anti-tumor drugs based on angiogenesis.